4.1 stars. Rigorous yet not obscurantist in its approach to time travel. Flashy, yet without obnoxious showboating. Plot developments which border on the sentimental, but feel earned. Basically, it's an exceptionally realized piece of otherwise standard science-fiction. Strange to think of such a humanistic work coming from Nitroplus and leagues ahead of the anime adaptation of their previous visual novel Chaos;Head.